More than 50% of persons with CP experience limitations in walking skills and physical activity. Moderate to severely impaired children with CP have been reported to have less than normal general and physical health. Lower QOL has been documented for adolescents with a broad spectrum of disabilities compared to non-disabled youth. Current therapies for CP focus primarily on treating impairments (spasticity, strength, limited range of motion) with the goal of improved walking activity, health and overall QOL. Before we can assess the efficacy of current treatments on the health and QOL of youth with CP, we must first describe the relationship of activity level to health and QOL. The specific aims of this study are to test the 1) mean differences in activity performance, self-reported health status and QOL by level of activity capacity in youth with CP and typically developing youth, controlling for age, gender, SES & current day outlook; 2) the associations between activity level (performance) and self-perceived health status and QOL in youth with CP and TDY, controlling for age, gender, SES and current day outlook, and 3) explore a model specifying the influence of activity capacity and activity performance on health status and quality of life controlling for age, gender, SES and current global QOL. A better understanding of the relationship of daily walking activity performance to the life experience of youth with CP will enhance the efficacy research of treatments for mobility impairments in youth with CP. [unreadable] [unreadable] [unreadable]